1. Field of the Invention
The present invention relates to a system and method for modulating a carrier frequency, and more specifically, to a Microwave Landing System (MLS) modulated carrier frequency generator.
2. Description of Prior Art
In recent years, different techniques for realizing a carrier frequency modulator in a compact circuit have been developed, and particularly for a carrier frequency modulator working at the microwave frequency range. Among these techniques, microwave integrated or hybrid circuits have been proposed in the design of microwave generators or modulators, However, these circuits being generally expensive and complex, there is still a need for a less expensive circuit using simpler technology, such as microstrip circuit manufacturing technique, while presenting high stability and high modulation accuracy characteristics. Moreover, both current integrated or hybrid circuit realizations generally require electric power supply showing a high power output rating, due to the high power dissipation occurring during the operation or these circuits. Especially for portable units operating with battery packs, current generators or carrier frequency modulators using integrated or hybrid circuits cannot feature sufficient low power consumption to provide proper power autonomy while using small battery packs, thereby increasing physical dimensions and weight of such portable units. This low power consumption requirement is of a particular importance for portable MLS generators, which are currently used for ramp testing of airplane inboard MLS receivers.